Wideband optical sensor and use thereof in dispensing systems

Abstract

Apparatuses, methods, and software products for analyzing liquids dispensed from a chemical dispensing system. Beams of light having different wavelengths are passed through a liquid dispensed by the dispensing system. The intensity of each beam of light is measured after passing through the liquid. A transmission coefficient is determined by comparing the intensity of the beam of light to a calibration parameter obtained by passing the beam of light through an unadulterated diluent. The transmission coefficients for the beams of light are then compared to corresponding transmission coefficients obtained for one or more known reference solutions to determine one or more characteristics of the liquid being dispensed from the chemical dispensing system.

What is claimed is: 
     
       1. An apparatus for analyzing a liquid, comprising:
 one or more photodetectors; 
 a first light source configured to generate a first beam of light that has a first wavelength, passes through the liquid, and illuminates at least one of the one or more photodetectors after passing through the liquid; 
 a second light source configured to generate a second beam of light that has a second wavelength different from the first wavelength, passes through the liquid, and illuminates at least one of the one or more photodetectors after passing through the liquid; 
 a processor; and 
 a memory storing program code that, when executed by the processor, causes the apparatus to: 
 when the liquid is a first solution:
 receive a first signal from the one or more photodetectors indicative of a first intensity of the first beam of light, 
 receive a second signal from the one or more photodetectors indicative of a second intensity of the second beam of light, 
 determine a first transmission coefficient based on the first intensity, and 
 determine a second transmission coefficient based on the second intensity; 
 
 when the liquid is a second solution:
 receive a third signal from the one or more photodetectors indicative of a third intensity of the first beam of light, 
 receive a fourth signal from the one or more photodetectors indicative of a fourth intensity of the second beam of light, 
 determine a third transmission coefficient based on the first intensity, and 
 determine a fourth transmission coefficient based on the fourth intensity; 
 
 determine a first difference between the first transmission coefficient and the third transmission coefficient; 
 determine a second difference between the second transmission coefficient and the fourth transmission coefficient; and 
 determine a characteristic of the first solution based on the first difference and the second difference. 
 
     
     
       2. The apparatus of  claim 1  further comprising:
 a chamber configured to receive the liquid so that the first and second beams of light pass through the liquid in the chamber. 
 
     
     
       3. The apparatus of  claim 2  wherein the chamber includes at least a portion of a machine supply line. 
     
     
       4. The apparatus of  claim 2  wherein the chamber includes a connector configured to couple the chamber to a machine supply line. 
     
     
       5. The apparatus of  claim 1  wherein the program code is further configured to cause the apparatus to:
 sequentially activate the first light source and the second light source, the first signal being received in response to activating the first light source, and the second signal being received in response to activating the second light source. 
 
     
     
       6. The apparatus of  claim 1  wherein the characteristic is a type of a chemical product in the liquid, a concentration of the chemical product in the liquid, or both the type and the concentration of the chemical product in the liquid. 
     
     
       7. The apparatus of  claim 1  wherein the first solution is a working solution, and the second solution is a reference solution having a known characteristic. 
     
     
       8. The apparatus of  claim 1  wherein the first solution is one of a working solution or a reference solution, the second solution is an unadulterated diluent, and the program code further causes the apparatus to:
 store the third intensity as a first baseline calibration parameter in the memory; and 
 store the fourth intensity as a second baseline calibration parameter in the memory, 
 wherein the first transmission coefficient is determined by comparing the first intensity to the first baseline calibration parameter, and 
 the second transmission coefficient is determined by comparing the second intensity to the second baseline calibration parameter. 
 
     
     
       9. A method of analyzing a liquid, comprising:
 when the liquid is a first solution:
 passing a first beam of light having a first wavelength through the liquid, 
 measuring a first intensity of the first beam of light after passing through the liquid, 
 determining a first transmission coefficient based on the first intensity, 
 passing a second beam of light having a second wavelength different from the first wavelength through the liquid, 
 measuring a second intensity of the second beam of light after passing through the liquid, and 
 determining a second transmission coefficient based on the second intensity; 
 
 when the liquid is a second solution:
 passing the first beam of light through the liquid, 
 measuring a third intensity of the first beam of light after passing through the liquid, 
 determining a third transmission coefficient based on the third intensity, 
 passing the second beam of light through the liquid, 
 measuring a fourth intensity of the second beam of light after passing through the liquid, and 
 determining a fourth transmission coefficient based on the fourth intensity; 
 
 determining a first difference between the first transmission coefficient and the third transmission coefficient; 
 determining a second difference between the second transmission coefficient and the fourth transmission coefficient; and 
 determining a characteristic of the first solution based on the first difference and the second difference. 
 
     
     
       10. The method of  claim 9  wherein the first solution is a working solution, and the second solution is a reference solution having a known characteristic. 
     
     
       11. The method of  claim 10  further comprising:
 storing the third and fourth transmission coefficients in a memory as chemical calibration parameters. 
 
     
     
       12. The method of  claim 9  wherein the characteristic of the liquid is a type of a chemical product in the liquid, a concentration of the chemical product in the liquid, or both the type and the concentration of the chemical product in the liquid. 
     
     
       13. The method of  claim 9  wherein the first solution is one of a working solution or a reference solution, the second solution is an unadulterated diluent, and further comprising:
 setting a first baseline calibration parameter based to the third intensity; and 
 setting a second baseline calibration parameter based on the fourth intensity, 
 wherein the first transmission coefficient is determined by comparing the first intensity to the first baseline calibration parameter, and 
 the second transmission coefficient is determined by comparing the second intensity to the second baseline calibration parameter. 
 
     
     
       14. The method of  claim 9  wherein the first intensity and the second intensity are measured using a single photodetector. 
     
     
       15. The method of  claim 9  wherein the first beam of light and the second beam of light are passed through the liquid sequentially. 
     
     
       16. The method of  claim 9  further comprising:
 receiving the liquid in a chamber, wherein the first beam of light and the second beam of light are passed through the liquid in the chamber. 
 
     
     
       17. A computer program product for analyzing a liquid, the computer program product comprising:
 a non-transitory computer-readable storage medium; and 
 program code stored on the non-transitory computer-readable storage medium that, when executed by one or more processors, causes the one or more processors to: 
 when the liquid is a first solution:
 pass a first beam of light having a first wavelength through the liquid, 
 measure a first intensity of the first beam of light after the first beam of light has passed through the liquid, 
 determine a first transmission coefficient based on the first intensity, 
 pass a second beam of light having a second wavelength different from the first wavelength through the liquid, 
 measure a second intensity of the second beam of light after the second beam of light has passed through the liquid, and 
 determine a second transmission coefficient based on the second intensity; 
 
 when the liquid is a second solution:
 pass the first beam of light through the liquid, 
 measure a third intensity of the first beam of light after passing through the liquid, 
 determine a third transmission coefficient based on the third intensity, 
 pass the second beam of light through the liquid, 
 measure a fourth intensity of the second beam of light after passing through the liquid, and 
 determine a fourth transmission coefficient based on the fourth intensity; 
 
 determine a first difference between the first transmission coefficient and the third transmission coefficient; 
 determine a second difference between the second transmission coefficient and the fourth transmission coefficient; and 
 determine a characteristic of the first solution based on the first difference and the second difference.